The present invention relates to an image forming apparatus such as a printer, a facsimile machine, a copier or a multi-function peripheral having a fixing unit for fixing a toner (i.e., a developer) to a recording medium.
In a conventional image forming apparatus, a warming-up operation is performed for preheating a fixing unit before a printing operation is started. In the warming-up operation, one of two heat sources of a fixing roller is heated so as to uniformly heat a center portion and both end portions of the fixing roller in a longitudinal direction (for example, Japanese Application Publication Document No. 2012-118140).
Further, in order to prevent the fixing unit from performing a fixing operation with the excessively heated fixing roller, a cooling-down operation is performed after the printing operation is finished (for example, Japanese Application Publication Document No. 2004-102104).
In the warming-up operation or the cooling-down operation, the fixing roller is rotated in a state where the recording medium such as a continuous sheet remains in the fixing unit. Therefore, the recording medium may be transported during the warming-up operation or the cooling-down operation, and may be unnecessarily ejected.